Laternula elliptica

The team of Ahn et al. used a PVC corer to sample habitat sediment relevant to the clam Laternula elliptica from the Collins Harbour (Maxwell Bay, King George Island) at a depth of 30 cm (42). Samples were extracted with high-purity HNO3 after oven-drying. Cadmium, Co, Cr, Fe and Zn were measured by F-AAS and ETA-AAS in an attempt to clarify the mechanism of bioaccumulation of the metals in the organism. 

At Potter Cove, there are some molluscs that meet the prerequisites to be considered as a useful biomonitor, such as the clam Laternula elliptica and the gastropod Nacella concinna. 

Laternula elliptica, one of the largest bivalves in the Antarctic marine environment, has been proposed as a biomonitor of trace metals in coastal waters (67, 70). Although gastropod molluscs have been less extensively used for monitoring trace metals pollution that mollusc bivalves, they show eharacteristics useful for these studies (61). The limpet Nacella concinna is the most abundant and often the only invertebrate found in the littoral zone of the Antarctic peninsula. 

Table 6.13. Trace metals contents in whole tissue of Adamussium colhecki and Laternula elliptica from Antarctica (ng g , dry weight)...

Mean Cd, Cu and Zn contents in whole tissue of Antarctic bivalves are compared in Table 6.13. Copper levels detected in bivalves from Potter Cove were higher than those observed in bivalves from East Antarctica. The levels of Cu detected in Laternula elliptica are consistent with the high values of Cu observed in limpet, marine surface sediments and suspended particulate matter. While Zn levels were in agreement with the values reported for Adamussium colhecki, those of Cd were significantly lower in Laternula elliptica. 

Cadmium concentrations reported for Adamus.sium colhecki from Terra Nova Bay and Syowa Station were almost one order of magnitude higher than levels found in Laternula elliptica from Potter Cove. The marked bioaccumulation of Cd found in molluscs from East Antarctica was related to two main reasons i) the high bioavailability of this metal in the Antarctic marine environment ii) the high potential of these organisms for metal bioaccumulation (67, 70, 74). 

The low Cd levels observed in Laternula elliptica from Potter Cove might be due either to the low phytoplankton biomass available for consumption or to the possible utilization of alternative food sources. Likewise, alternative food sources... 

Table 6.14. Trace metals contents (mean + sd or range) in Adamussium colbecki and Laternula elliptica from Antarctica...

Figure 6.10. Trace elements contents (ng g wet weight) in Laternula elliptica.

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